This invention relates to packaging for semiconductor photovoltaic devices known generally as solar cells.
Photovoltaic devices present unique problems requiring specialized packaging to achieve desired levels of durability, mechanical integrity, electrical connectivity and convenience of mounting. Because such devices are exposed continuously to a wide range of thermal and weather conditions, packaging must be moisture-proof and tolerant of thermal expansion and contraction. The packaging must also lend itself to a low cost and highly automated manufacturing process. The delicate semiconductor material used as the operative portion of a solar cell must be protected from excessive current by attaching, for example by use of an additional device such as a bypass diode in parallel with the anode and cathode of the device, an operation normally accomplished by wire or ribbon bonding in a manner that may cause high rates of mechanical failure in actual usage. Further, suppliers of photovoltaic cells and systems are increasingly required to guarantee that their products will operate without replacement for long periods of time, in some cases up to 30 years or more. The packaging for such cells must therefore provide durability as well as reliability.